Method of obtaining contact in processed-paper printing



June 22 1926 1,589,811

w. w. MATHES METHOD OF OBTAINING CONTACT IN PROCESSED PAPER PRINTING D Filed June 1, 1925 IN V EN TOR.

William WMathes Q inky- A TTORNEY Patented june 22, 1926. v

"UNI TED STA T E S P AT '0 F F '1 C E METHOD OF OBTAINING CONTACT IN PROCESSED-PAPER PRINTING.

Application filed June 1, 1923. Serial No. 642,752.

This invention relates to what is comhaving a smoother surface, absolutely true monly known as the blue-printing industry, and level, and the size of the frame. in which negatives and blue or other prints In placing this pad over the sheets 3 and are obtained from drawings, etc., on trac- 4, it is first rolled up as shown, and placed 5 ing cloth or paper, or from negatives first at one end of the frame, in such a manner obtained from the same, by exposure to the that the unrolling of the pad will cause the light. same to extend toward the other end of the It is essential to obtain good results from frame. any tracing or negative that the contact be- The pad, being heavy and very flexible will,

' tween the latter and the paper on which the as it unrolls, lie absolutely flat on the sheets print is being made shall be good, as otherthereunder, forcing all air from between wise a blurred effect will be had. This is he sheets, and by reason of its weight and frequently hard to obtain however owing to rolling movement, flattening out all creases creases, bulges and the like in one or the and the like therein as the pad advances.

' other of the contacted sheets. To overcome Apart from its weight however, the excluthis, vacuum printing frames are commonly sion of the air from. between the sheets, used, which necessitates a considerable Outand from between the uppermost sheet and lay for air pumps and the accessories which the pad, will cause a certain suctional 111- go with the same. This system, while good, fiuence to be set up between the pad and the 20 1s expensive to operate, and the high negamembers thereunder, so that the normal tive pressures sometimes used are apt to pressure of air on the outer surface of the cause the glass of the printing frame to be pad will be added to its weight to cause the broken. pad to be firmly held against the sheets, and

The principal object of my invention the latter against themselves.

therefore is to eliminate the above named Though it may be possible to effect this expense and defects of operation by proexclusion of the air, which is one of the viding method for obtaining excellent conmain features of my method, by other means tact without the use of mechanism of any than by unrolling the pad, this is such a character, with a small initial cost, and withsimple and quickly performed operation,

30 out any expense for operation. that I feel it is the only practical method The manner in which I attain my ends to employ. will be made fully evident by a further It is also essential of course that the pad perusal of this specification, reference being shall be air proof, and quite flexible and had to the accompanying drawing, the figure heavy, so that when the pad is rolled up it on which is a perspective View of a blue Will haw e a tendency to unroll under its own printing frame of ordinary character, showflexibility and weight and thus as it unrolls ing my contact-obtaining means therein. and lays flat against the sheet it will auto- Referring now,more particularly to the matically expel the air from between the characters of reference on the drawing, the pad and sheet. numeral 1 denotes the frame, having the Here again, while there may be other usual smooth glass 2 against the inner face materials than rubber suitable for the purof which the negative or tracing 3 is placed, pose, I feel that rubber, of the proper quality on which in turn the sheet of processed and weight, is the best material obtainable. paper 4 to be printed, is laid. It will therefore be evident that I have To obtain the desired and necessary conprovided a method and device for the purtact between the sheets 3 and 4, I employ a pose which will be very efficient in operafairly heavy sheet or pad 50f pure rubber, tion, whether for small or large frames.

face consisting in placing on said sheets a padof heavy flexible and air proof material rolled on itself, and allowing the pad to unroll over the sheets under the influence of its own 'Weight and resiliency whereby with such unrolling of the pad the air between the pad and sheets Will be positively excluded.

In testimony whereof I afix my signature.

WILLIAM WV. M ATHES. 

